1. Field of the Invention
The present invention relates to an electrophotographic photosensitive member, a process cartridge and an electrophotographic apparatus each including the electrophotographic photosensitive member, and an imide compound.
2. Description of the Related Art
Electrophotographic photosensitive members containing organic photoconductive materials (charge generation materials) have been mainly used as electrophotographic photosensitive members for use in process cartridges and electrophotographic apparatuses. Electrophotographic photosensitive members advantageously have high productivity because they can be produced by coating with good film formability.
Typically, an electrophotographic photosensitive member includes a support and a photosensitive layer disposed on the support. To inhibit the charge injection from the support side to the photosensitive layer side and inhibit the occurrence of image failure, such as black spots, an undercoat layer is often provided between the support and the photosensitive layer.
However, the presence of the undercoat layer reduces the properties of the electrophotographic photosensitive member, in some cases.
In Japanese Patent Laid-Open Nos. 2007-148294 and 2008-250082 and PCT Japanese Translation Patent Publication No. 2009-505156, attempts are made to improve the properties of the undercoat layer by incorporating an electron transport material into the undercoat layer to allow the undercoat layer to serve as an electron transport layer. In the case where the electron transport material is incorporated into the undercoat layer, a technique is reported in which the undercoat layer is cured to form a cured layer in such a manner that the electron transport material is not eluted with a solvent in a photosensitive layer coating liquid upon forming a photosensitive layer serving as an upper layer of the undercoat layer.
In recent years, charge generation materials having higher sensitivities have been used. A higher sensitivity of a charge generation material result in a larger amount of charges generated; hence, the charges are liable to stay in the photosensitive layer, thereby easily causing a positive ghost. There have recently been advances in improvement in image quality typified by colorization. This requires a further reduction of the positive ghost. The positive ghost refers to a phenomenon in which, in the course of formation of an image on a sheet, when a portion irradiated with light is responsible for a halftone image in a next rotation, the density of only the portion irradiated with light is increased.
The inventors have conducted studies and found that the techniques disclosed in Japanese Patent Laid-Open Nos. 2007-148294 and 2008-250082 and PCT Japanese Translation Patent Publication No. 2009-505156 still have room for improvement in the reduction of the initial positive ghost.